Platinum nanoparticles confined within TiO₂ nanotube matrix for enhanced catalytic reduction of azure b dye

In this work, we report the synthesis of TiO₂ nanotubes encapsulated platinum nanoparticles (PtNPs-TiO₂NTs) as a highly efficient catalyst for the catalytic reduction of azure B (AZB) dye in the sodium borohydride (NaBH₄) medium. The encapsulation of PtNPs (particle size ∼ 2–3 nm) inside the TiO₂NTs was confirmed by HR-TEM analysis. The as-prepared PtNPs-TiO₂NTs exhibit higher conversion efficiency than 99 % with a pseudo-first order rate constant of 2.6 × 10^-3 s⁻¹. Owing to the confinement effect of PtNPs inside the TiO₂NTs, the synthesized catalyst shows the superior operative stability even after 8 consecutive recycles without any loss in its activity. This work opens up new avenue for the designing of confined catalyst for various industrial catalytic reactions.